Recently, with the development of digital technologies, various user devices including mobile communication electronic devices, Personal Digital Assistants (PDA), electronic organizers, smart phones, tablet Personal Computers (PC), and the like which can perform communication and personal information processing while being carried have come to market.
Through rapid development of these technologies, the user devices have various functions such as a video call function, an electronic organizer function, a photography function, an e-mail transmission/reception function, a broadcasting reproduction function, an internet function, a music reproduction function, a schedule management function, a Social Networking Service (SNS) function, a messenger function, a dictionary function, a game function, and the like in addition to a voice call function and a short message transmission function of the initial stage.
The aforementioned functions can be basically loaded when the user devices are manufactured, and users can download applications having new functions from application stores and additionally install them according to the user's needs.
For multi-tasking, applications may be divided into an application executed in the foreground and an application executed in the background.